Gearing for marine propulsion and the like



Jufly 17, 1923- K. ALQUIST GEARING FOR MARINE PROPULSION AND THE LIKE Filed March 19. 1920 Inventor: Kar-l /-\I u;ist

K is a specification.

Patented July 17, 1923..

entree eras KARLKALQUIST, OF NEW YORK, N. Y.

GEARING FOR MARINE PROPULSION AND THE LIKE.

Application filed March 19, 1920. Serial No. 367,158.

transmission of power from a prime mover to the propeller shaft or a vessel through I spur gearing.

It is now known that in a roughsea the power'thus transmitted is subject to wide variations, the period of the variations being substantially dependent upon the pitching of the vessel. The prime mover, generally a steam turbine revolving at a high speed, has a comparatively large fly wheel capacity, while'the propeller with its shaft and'the driven portion of the gear have a small is; wheel capacity. In the case of a double reduction gearing, the prime mover and high speed end of the gearing may be considered a high speed system, and the'propeller and low speed end of the gearing alow speed system. The body of water in whichthe propeller rotates will, due tothe action of the waves, periodically vary its speed relatively to the ship in the direction of motion of the ship and it thus may happen that at times the propeller, instead of being driven by the gear, is driven by the water. lVhen this happens, the prime mover referred towill speed up the system, but in a heavy sea it may happen that the propeller is accelerated by the water at a higher rate than that of the prime mover, due to the unequal fly wheel effects of the two ends of the system before referred to. In such a case, the normal driving portion of the gear will be driven, resulting'in 'a shifting of the teeth inmesh through the clearance space-tozcoa tact on the other sides of the teeth. The continuity of the driving pressure and contact is 'thus broken and when the normal direction of drive is reestablished, i'. e.. when the propeller hits the water again there results a large, temporarily increased pressure on the gear teeth due to the speeding up of the system during the period described, and this pressure is further increased by a blow between the teeth. Also when the pin ion does not drive, it generally moves endwise from its normal position and,v when i the drive comes on, will oscillate with blows before steadying down. It is evident that the increase in pressure between-the gear teeth due to theblows is substantial, and as the life of the gear'is dependent upon keeping down their maximum pressure peaks'as far as possible, the importance of maintaining the continuity of drive and avoiding such blows is apparent.

The object of my invention is to provide an improved structure and arrangement in a gearing for marine propulsion wh'erebythe above referred to difliculties-will be overcome, and for a consideration of what I believe to be novel and my'invention, attention is directed to the following description and the claims appended thereto. I

In the drawing, Fig. 1 is a diagrammatic plan view of a gearing embodying my invention, and Fig; 2 is an end View'thereof. v

Referring to the drawing, 5 indicates a propeller shaft driving a shipspropeller 6. On the shaft 5 is a low speed gear wheel 7 which is shown as meshing withftwo low speed pinions 8 and 9 mounted on intermediate speed shafts '10 and 11 respectively.

On shafts 10 and 11 are high speed' g'ear able prime movers such as elastic-fluid turbines, an arrangement as shown beingwell adapted for use in connection witha high pressure turbine and a low pressure turbine connected in series as regards the'fiow of operating'fluid. The foregoing forms a double reduction gearing, pinions 14 and 15 and gear wheels 12-and 13 forming the high speed end, and pinions '8 and 9 and gear wheel 7 forming the low speed'end. High speed gear wheels 12 and13-are sho'wnt-a's being of the 'fieXible type invented by me and comprising a plurality of disks or 'plates rigidly fastened together at'their-central portionsand spaced slightly apartattheir peripheries to permit of axial yielding under excessive tooth pressure.

Now, according to my invention, Innake the low speed gearzwheel 7 of rather large diameter thereby increasing its fly wheel effect and provide it and the low speed pinions 8 and 9 with which it meshes with single helical gear teeth of small angle, for example about 5 degrees. for each. of the intermediate speed shafts 10 and Y11,"; suitable thrust bearings 18 and 19 which firmly hold the intermediate speed parts of the gearing against axial move ment. The high speed'endof the" gearing has preferably double helicalteeth as shown.

With this arrangement when a reversal of end thrust occurs on the. propeller shaft and stances-any violent axial shiftings or vibra-.

tions of the; low speed'end of the gearing such as may occur for example-with double helical gearing inthelow speed end. The

mason for this is that with double helical teeth on the low speed end ofthe gearing the intermediate speed portion of the, gearing, i; e;., the intermediate speed shaft or shaftswhich carry the low speed pinions andthe high speed gear Wheels is liable to Slide axially-toward one end under the force ofgravity or for other reasonswhen the loadis taken ofi'thepropeller by the pro peller being driven'by the water, and when the load suddenly comes on again, the inter mediate speed portion of the gear being then driving onone; helix, is violently moved ba'clraxially'and overruns its middle position and drives onthe other helix after which it will be thrown back again, thus oscillating with hard blows afew times for each period" the load is thrown on; These blowszare especially destructive. With my improvedarrangement, I hold the intermediate speed portion of the gearing firmly against movement in an axial direction by the thrustbearings- 18 and v19wwith the re sult that an action such as that just de scribed cannottake place.

Since gear'wheel 7 has a large diameter, its width will be comparatively small and hence the length and diameter of the low speed pinion or pinions meshing therewith will'have satisfactory proportions Furthermore on account of the small angle oft-he teeth. on gear wheel 7 it is able to move axially thereby following the i'breathin'gs or small movementsrof the main thrust bearing for the, propeller shaft without any appreciable effort on the rest of the gearing. At the same time the smooth running characteristics of helical gearing is retained eventhough the helical angle is comparatively small. The main thrust hearing for the propeller shaft does not show in. the drawing, but it will be understood that it is of the usual type for taking the axial thrust of the propeller shaft.

In accordance with the provisionsofthe patent statutes, I have described the principle of operation of my invention, together with the apparatuswhichl now consider to represent the best embodiment thereof;

but I desire to haveitunderstood that the apparatus shown. is only illustrative, I and that the invention,mayv be carried. out by other means.

What I claim as new and desire to secure by Letters Patent of the United'States, is, v

1. In a ship propulsion gearing, the combination'of a propeller shaft, a. low speed gear wheel mounted thereon, said gear wheel having single helical teeth of an, angle of the order of five degrees, a high speed pinion, an intermediate speedshaft carrying a low speed pinion, and a high; speed gear wheel which mesh with said low speedv gear wheel and high speed pinion respectively,

said high speed pinion and high speedv gear fly wheel effect will be large, a high speed j pinion, an intermediate speed shaft car-rying a low speed pinion and-a high speed gear wheel which mesh. with said low speed gear wheel and; high speed pinion respectively, said high speed pinion and high speed gear wheel being of the double helical type, and said; low speed pinion being of the single helical type for meshing with the low speed gear wheel, and a thrust bearingfor said.

intermediate speed shaft to take the axial thrust tothesingle helical low speed pinion. In witness whereof, I have hereunto set my hand this tenth day of March, 1920.

KARL ALQUIST. 

